Enhanced visible light catalytic activity of MoS2/TiO2/Ti photocathode by hybrid-junction

In photoelectrochemical (PEC) water splitting systems, crucial obstacles limiting their performance are poor charge carrier dynamics and high recombination rate of photoexcited electron-hole pairs. Here, we report that this issue can be alleviated by engineering a hybrid junction that is composed of homo- and hetero-junctions. This strategy is performed by facile hand-spraying MoS2 over the surface of anatase/rutile homo-junction TiO2 film on the Ti substrate to further form a hybrid junction photocathode. By applying this photocathode into PEC reactor, enhanced catalytic activity is achieved under visible light (AM1.5 illumination of 300 W/m(2)) with hydrogen evolution reaction (HER) potential of -114 mV versus reversible hydrogen electrode (RHE) at 10 mA/cm(2) and long-term stability of more than 10 times improvement comparing to ordinary electrode without the introduction of hybrid-junction. The hybrid-junction that effectively regulates charge separation and transfer pathways is proven to be responsible for the enhanced activity. As a novel exploration, this hybrid-junction system comprising of low-cost, efficient charge separation and transfer, and visible light responsivity offers a new path for relative materials to boost their PEC performance.